With the advent of high speed copiers, such as xerographic reproduction machines, automatic document handlers have been developed to rapidly place and remove documents from the platen of the copy machine to enable the machine to produce copies at its full potential. Following separation of the document to be copied from the remainder of the documents awaiting copying, the separated document must be brought into position on the machine platen and located in a certain position to assure the making of a complete and visually acceptable copy. To assure that the document is positively driven onto the platen of the copy machine and accurately located thereon, a platen belt overlying the entire platen area may be utilized. To prevent printing of "black borders" due to copying documents on larger size sheets than the original document, the platen belt is ordinarily formed of a white material to enable discharge of the photoconductive surface in the border areas and thereby prevent printing the black borders on the finished copy.
In positioning the document on the platen, it is common to drive the document onto the platen and thereafter reverse the belt movement to drive the document into a registration edge to assure accurate positioning of the document. In driving the documents against the stationary registration edge, the normal force between the belt and the document and the frictional force therebetween must be carefully controlled to prevent jamming of the document against the registration edge and wrinkling or otherwise damaging the lead edge of the document.
After the document handler has been in use for a certain number of cycles, the white surface of the belt becomes soiled, either with ink material picked up from the back side of the documents being copied or by normal dust that may settle on the glass when the platen belt is moved away from the platen for access thereto. When the platen belt surface becomes soiled, the soil marks may be printed through on the final copy, resulting in an unacceptable "dirty" copy. As such, the machine operator periodically must clean the platen belt to restore the white reflective surface desired.
However, immediately after cleaning the belt surface, the coefficient of friction of the surface is maximized. As the belt is used, the coefficient of friction drops to a lower level. Since the coefficient of friction reaches this lower level a short period of time after the cleaning operation has been performed, the belt material and the normal forces are ordinarily selected in the design of an automatic document handler utilizing this lower coefficient of friction. However, because of the higher frictional characteristics obtained immediately after cleaning, it has been found that document damage may occur upon reversal of the platen belt when driving the document against the cooperating registration edge.
It is therefore an object of this invention to provide a method for treating automatic document handler belts which provides a reduced belt coefficient of friction immediately after the belt has been cleaned to allow immediate use of the reproduction machine and assure proper document handling.